The oncogenic role of U2AF2/HKDC1 cascade in colorectal cancer by promoting cancer cell glycolysis and malignant phenotypes.

[BACKGROUND] Dysregulation of hexokinase domain component 1 (HKDC1), a central regulator of glucose metabolism, plays a pathogenic role in colorectal cancer (CRC). The current research investigated the RNA-binding protein (RBP)-mediated mechanism in driving HKDC1 dysregulation in CRC.

[METHODS] Expression of mRNAs was detected by quantitative PCR, and protein expression analysis was performed by immunoblot and immunohistochemical assays. Cell invasiveness, migration, apoptosis, colony formation and proliferation were evaluated by transwell, wound healing, TUNEL staining, colony formation, and CCK-8 assays, respectively. Glucose consumption and lactate production were quantified to examine glycolysis. Luciferase, RNA immunoprecipitation (RIP) and mRNA stability assays were used to confirm the U2AF2/HKDC1 relationship. Xenograft models were established to examine the in vivo function.

[RESULTS] In human CRC, HKDC1 and U2AF2 were present at higher levels, and HKDC1 expression was positively associated with U2AF2 level. Cells with HKDC1 depletion presented repressed growth, enhanced apoptosis, reduced migratory capacity, as well as suppressive invasiveness and glycolysis. Mechanistically, U2AF2 stabilized HKDC1 mRNA and induced HKDC1 protein upregulation. Depletion of U2AF2 decreased cell growth, migratory capacity, invasiveness, and glycolysis and promoted apoptosis in vitro, as well as diminished the in vivo tumorigenicity of HCT116 cells, which could be partially abolished by HKDC1 increase.

[CONCLUSION] Our observations demonstrate that U2AF2 works as an mRNA-stabilizing factor for HKDC1, and the U2AF2/HKDC1 axis contributes to CRC glycolysis and development. Targeting the novel axis might form the basis of a promising therapy for CRC treatment.